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Metabolic Bone Disorders

Metabolic Bone Disorders. Prof. Mohammed Zamzam Professor & Consultant Pediatric Orthopedic Surgeon. Calcium Homeostasis. - Bone is not only for support - Bone formation & bone resorption - Hydroxyapatite crystals - Calcium & phosphate control * Intestinal absorption

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Metabolic Bone Disorders

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  1. Metabolic Bone Disorders Prof. Mohammed Zamzam Professor & Consultant Pediatric Orthopedic Surgeon

  2. Calcium Homeostasis - Bone is not only for support - Bone formation & bone resorption - Hydroxyapatite crystals - Calcium & phosphate control * Intestinal absorption * Renal excretion * Bone

  3. Vitamin D * Sources - Diet - Ultraviolet rays on skin * Cholecalciferol activation - PTH - Phosphate concentration * Action - Intestinal absorption of Ca - Bone resorption

  4. Parathyroid Hormone - Fine regulator of Ca exchange - Serum Ca regulate its secretion - Action * Increase phosphate excretion * Increase Ca reabsorption * Vitamin D activation

  5. Calcitonin - C cells of thyroid gland - Serum Ca regulates its secretion - Action * Rapid hypocalcaemic effect by inhibiting bone resorption

  6. - Estrogen - Corticosteroids - Thyroxin - Mechanical stress - Prostaglandin E - Acid-base balance Secondary ruleOther Hormones Non-hormonal Factors

  7. Rickets & Osteomalacia - Different expressions of the same disease - Inadequate mineralization - Rickets * Areas of endochondral growth - Osteomalacia * All skeleton is incompletely calcified

  8. Rickets & Osteomalacia * Causes - Calcium deficiency - Hypophosphataemia - Defect in Vitamin D metabolism nutritional underexposure to sunlight intestinal malabsorption liver & kidney diseases

  9. Rickets & Osteomalacia Symptoms & Signs *Rickets - Tetany or convulsions ? - Failure to thrive , muscle flaccidity - Craniotabes , joint thickening - Pigeon chest , rickety rosary , Harrison’s sulcus - Deformities

  10. Rickets & Osteomalacia Symptoms & Signs *Osteomalacia - Bone pain , backache - Muscle weakness - Vertebral collapse kyphosis loss of height - Deformities & stress fractures

  11. Rickets & Osteomalacia Biochemistry Hypocalcaemia,… Hypocalcuria High alkaline phosphatase

  12. Rickets & Osteomalacia X-rays *Rickets - Growth plate widening & thickening - Metaphyseal cupping - Diaphyseal deformities *Osteomalacia - Looser zone , biconcave vertebra , protrusio acetabuli - Spontaneous fractures *Signs of secondary hyperparathyroidism

  13. Rickets & Osteomalacia Treatment *Vitamin D deficiency - Rickets controlled Vitamin D sun exposure correct residual deformities - Osteomalacia Vit. D + Ca fracture management correct deformity if needed

  14. Hyperparathyroidism *Primary hyperplasia - adenoma - carcinoma *Secondary persistent hypocalcaemia *Tertiary secondary leads to hyperplasia

  15. Hyperparathyroidism Pathology - PTH overproduction - Increased renal tubular absorption , intestinal absorption and bone resorption of Ca - Hypercalcaemia and hypercalciuria - Suppressed phosphate tubular reabsorption - Hypophosphataemia and hyperphosphaturia

  16. Hyperparathyroidism Pathology *Hypercalcaemia calcinosis , stone formation , recurrent infection and soft tissue calcification *Bone resorption loss of bone substance , subperiosteal erosion osteitis fibrosa cystica and brown tumors

  17. Hyperparathyroidism Symptoms & Signs *Hypercalcaemia anorexia , nausea , depression and polyuria *Bone rarefaction pain , pathological fractures and deformities *Biochemistry hypercalcaemia , hypophosphataemia , high alk. Phosphatase and serum PTH

  18. Hyperparathyroidism X-rays - Subperiosteal bone resorption - Generalized decrease in bone density - Brown tumors - Chondrocalcinosis knee , wrist and shoulder

  19. Hyperparathyroidism Treatment Surgical excision of adenoma or hyperplastic parathyroid tissue *Hungry bone syndrome treated by vitamin D

  20. Osteoporosis * Normal mineralization * Decrease bone mass (amount of bone per unit volume) * Age related * Associated or manifestation of other conditions

  21. Osteoporosis Causes * Idiopathic * Nutritional * Endocrine disorders * Drug induced * Malignant diseases * Miscellaneous

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